The invention relates to a method and apparatus for destroying weeds in and around crop rows, preferably utilizing high voltage electricity, and utilizing the geometry of the crop rows to ensure proper positioning of the plant destroying means (e.g., high voltage electricity) utilized. Prior apparatus for destroying plants in and around crop rows, and the like, is disclosed in U.S. Pat. Nos. 3,919,806 and 4,094,095. While the mechanisms disclosed in those patents are useful for a wide variety of situations, they have some limitations in specific situations. For instance, when the tractor driver is not particularly experienced, or wherein operation is taking place under adverse circumstances, sometimes is it difficult to ensure that the plant contacting probes are properly aligned with respect to the crop rows. The present invention, however, by taking advantage of the straight-line geometry of crop rows is able to ensure that the plant destroying probes are generally properly positioned with respect to the crop plants even should the tractor wander slightly.
According to one aspect of the apparatus according to the present invention, there is provided a frame mechanism adapted to move in a given direction; first and second probes; plant destruction means associated with each of the probes; and means for mounting each of said probes so that extend into a crop row from opposite sides thereof. There further is provided first pivot means for mounting each of the probe mounting means for pivotal movement with respect to the frame mechanism about a vertical axis, the vertical axes of the pivot means horizontally spaced from each other so that the probes are mounted on opposite sides of the rows; and means for operatively tying the probe mounting means together so that the probes will move with each other about their respective vertical axes so that they will engage the crops and center the plant destruction means utilizing a crop row.
The plant destruction means preferably comprises a high voltage source of electricity directly connected up to the probes, which are of conductive material. The probes preferably extend at a slant rearwardly away from the frame mechanism, opposite the given direction. Third and fourth probes may also be provided operatively connected to the source of high voltage electricity, the third probe being associated with the first probe and extending toward the crops and the fourth probe being associated with the second probe and extending toward the crops. The third and fourth probes are dimensioned so that they can never horizontally overlap. Means are provided for adjusting the horizontal spacing of the first and second probes so that they may be disposed in a position wherein they horizontally overlap, or in a position wherein they are slightly horizontally spaced from each other.
Second probe means also preferably are provided for mounting the probes for pivotal movement about a horizontal axis opposite the given direction, so that the probes (and ceramic insulators to which they are operatively connected) may move out of the way of unyielding obstructions. Spring means are provided for biasing the probes to a predetermined position so that if a probe is moved by a force about the horizontal axis it will be returned to the predetermined position by the spring means when the force is removed.
The pivot means preferably comprise at least one strip of flexible non-conductive material such as fiber reinforced rubber. Each probe mounting means preferably includes a hollow prism of fiberglass and a ceramic insulator mounted by a yoke for pivotal movement about the horizontal axis with respect to the prism at the bottom thereof. A turnbuckle assembly is provided for tying together the prisms associated with the first and second probes, and preferably gangs of such first and second probes and associated mounting means are provided mounted behind a common frame mechanism.
According to one aspect of the method according to the present invention, weeds are destroyed in and around crop rows utilizing the apparatus described above, the probes being centered with respect to the crop rows by engaging the plants in the crop rows. According to another aspect of the method of the present invention, by utilizing the horizontally staggered first and third and second and fourth probes, or the like plant contacting components, weeds in and around crop rows will be destroyed by practicing the steps of sequentially: contacting all plants on either side of the crop rows with the high voltage source of electricity (third and fourth probes); terminating the contacting (spacing between first and third and second and fourth probes); and contacting all of the plants in and around the crop rows with the high voltage source of electricity (the overlapped first and second probes). It has been found that when a plant is contacted its resistivity unexpectedly and fantastically descreases. If at some later point the same plant is then contacted again, the second contacting probe will do a great deal more damage than the first contacting probe at the same applied voltage conditions. By taking advantage of this fact, and by contacting weeds around the plant rows twice and crops in the plant rows only once, the effectiveness of the weed control practicing the present invention is greatly enhanced.
According to a second aspect of the apparatus according to the present invention, an electrical plant contacting probe assembly for mounting on a vehicle adapted to move in a given direction is provided. The assembly includes a support; a ceramic insulator; a plant contactor of electrically conductive material; and an electrically conductive material member passing through the bottom of the ceramic insulator unconnected to the plant contactor. There is also provided means for mounting the ceramic insulator to the support so that it extends vertically, and for rotation about a horizontal axis opposite said given direction; and spring means for biasing the ceramic insulator to a predetermined position so that if the insulator is moved away from the predetermined position by a force, said spring means will return the insulator to the predetermined position once the force is removed. The plant contactor preferably comprises a spring contact finger having a first portion connected to said member; a second portion extending downwardly from the first portion; and third portion connected to the second portion and extending generally horizontally. In this way, it is possible to mount the insulator so that there is the least possibility of damage thereto or destruction of the dielectric constant thereof by contamination.
It is the primary object of the present invention to provide an effective method and apparatus for destroying weeds in and around crop rows. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.